| 1. |
- Darsalia, Vladimer, et al.
(författare)
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Glucagon-like peptide-1 receptor activation reduces ischaemic brain damage following stroke in Type 2 diabetic rats
- 2012
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Ingår i: Clinical Science. - : Portland Press. - 0143-5221 .- 1470-8736. ; 122:9-10, s. 473-483
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Tidskriftsartikel (refereegranskat)abstract
- Diabetes is a strong risk factor for premature and severe stroke. The GLP-IR (glucagon-like peptide-1 receptor) agonist Ex-4 (exendin-4) is a drug for the treatment of T2D (Type 2 diabetes) that may also have neuroprotective effects. The aim of the present study was to determine the efficacy of Ex-4 against stroke in diabetes by using a diabetic animal model, a drug administration paradigm and a dose that mimics a diabetic patient on Ex-4 therapy. Furthermore, we investigated inflammation and neurogenesis as potential cellular mechanisms underlying the Ex-4 efficacy. A total of seven 9-month-old Type 2 diabetic Goto-Kakizaki rats were treated peripherally for 4 weeks with Ex-4 at 0.1, 1 or 5 mu g/kg of body weight before inducing stroke by transient middle cerebral artery occlusion and for 2-4 weeks thereafter. The severity of ischaemic damage was measured by evaluation of stroke volume and by stereological counting of neurons in the striatum and cortex. We also quantitatively evaluated stroke-induced inflammation, stem cell proliferation and neurogenesis. We show a profound anti-stroke efficacy of the clinical dose of Ex-4 in diabetic rats, an arrested microglia infiltration and an increase of stroke-induced neural stem cell proliferation and neuroblast formation, while stroke-induced neurogenesis was not affected by Ex-4. The results show a pronounced anti-stroke, neuroprotective and anti-inflammatory effect of peripheral and chronic Ex-4 treatment in middle-aged diabetic animals in a preclinical setting that has the potential to mimic the clinical treatment. Our results should provide strong impetus to further investigate GLP-IR agonists for their neuroprotective action in diabetes, and for their possible use as anti-stroke medication in non-diabetic conditions.
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| 2. |
- Fransson, Liselotte, et al.
(författare)
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beta-cell adaptation in a mouse model of glucocorticoid-induced metabolic syndrome
- 2013
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Ingår i: Journal of Endocrinology. - : BioScientifica. - 0022-0795 .- 1479-6805. ; 219:3, s. 231-241
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Tidskriftsartikel (refereegranskat)abstract
- Glucocorticoids (GCs) are stress hormones primarily responsible for mobilizing glucose to the circulation. Due to this effect, insulin resistance and glucose intolerance are concerns in patients with endogenous overproduction of GCs and in patients prescribed GC-based therapy. In addition, hypercortisolemic conditions share many characteristics with the metabolic syndrome. This study reports on a thorough characterization, in terms of glucose control and lipid handling, of a mouse model where corticosterone is given via the drinking water. C57BL/6J mice were treated with corticosterone (100 or 25 mu g/ml) or vehicle in their drinking water for 5 weeks after which they were subjected to insulin or glucose tolerance tests. GC-treated mice displayed increased food intake, body weight gain, and central fat deposit accumulations. In addition, the GC treatment led to dyslipidemia as well as accumulation of ectopic fat in the liver and skeletal muscle, having a substantial negative effect on insulin sensitivity. Also glucose intolerance and hypertension, both part of the metabolic syndrome, were evident in the GC-treated mice. However, the observed effects of corticosterone were reversed after drug removal. Furthermore, this study reveals insights into beta-cell adaptation to the GC-induced insulin resistance. Increased pancreatic islet volume due to cell proliferation, increased insulin secretion capacity, and increased islet chaperone expression were found in GC-treated animals. This model mimics the human metabolic syndrome. It could be a valuable model for studying the complex mechanisms behind the development of the metabolic syndrome and type 2 diabetes, as well as the multifaceted relations between GC excess and disease.
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| 3. |
- Kappe, Camilla, et al.
(författare)
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Glucocorticoids suppress GLP-1 secretion : possible contribution to their diabetogenic effects
- 2015
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Ingår i: Clinical Science. - 0143-5221 .- 1470-8736. ; 129:5, s. 405-414
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Tidskriftsartikel (refereegranskat)abstract
- Evidence indicates that subtle abnormalities in GC (glucocorticoid) plasma concentrations and/or in tissue sensitivity to GCs are important in the metabolic syndrome, and it is generally agreed that GCs induce insulin resistance. In addition, it was recently reported that short-term exposure to GCs reduced the insulinotropic effects of the incretin GLP-1 (glucagon-like peptide 1). However, although defective GLP-1 secretion has been correlated with insulin resistance, potential direct effects of GCs on GLP-1-producing L-cell function in terms of GLP-1 secretion and apoptosis have not been studied in any greater detail. In the present study, we sought to determine whether GCs could exert direct effects on GLP-1-producing L-cells in terms of GLP-1 secretion and cell viability. We demonstrate that the GR (glucocorticoid receptor) is expressed in GLP-1-producing cells, where GR activation in response to dexamethasone induces SGK1 (serum-and glucocorticoid-inducible kinase 1) expression, but did not influence preproglucagon expression or cell viability. In addition, dexamethasone treatment of enteroendocrine GLUTag cells reduced GLP-1 secretion induced by glucose, 2-deoxy-D-glucose, fructose and potassium, whereas the secretory response to a phorbol ester was unaltered. Furthermore, in vivo administration of dexamethasone to rats reduced the circulating levels of GLP-1 concurrent with induction of insulin resistance and glucose intolerance. We can conclude that GR activation in GLP-1-producing cells will diminish the secretory responsiveness of these cells to subsequent carbohydrate stimulation. These effects may not only elucidate the pathogenesis of steroid diabetes, but could ultimately contribute to the identification of novel molecular targets for controlling incretin secretion.
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| 4. |
- Sundsten, Tea, et al.
(författare)
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Proteomics in diabetes research
- 2009
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 0303-7207 .- 1872-8057. ; 297:1-2, s. 93-103
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Forskningsöversikt (refereegranskat)abstract
- Both type 1 and type 2 diabetes mellitus are heterogeneous diseases with alterations in many genes and their products. Not all transcriptional alterations lead to protein changes, which makes it very important to, in conjunction with mRNA expression studies, also address changes in cellular protein levels. Various proteomic techniques are available for measuring many protein changes simultaneously. Many proteomic studies have been performed in the context of diabetes research, with the aims of both describing the healthy tissue and to unravel the complex pathophysiology behind the disease. In addition, effects on proteins induced by different treatments have also been investigated using proteomic approaches. In this paper the field of diabetes proteomics today will be reviewed. Findings from proteomic studies investigating pancreatic islets and beta-cells as well as serum, fat, skeletal muscle and liver are described.
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